Prosthesis joints



Sept. 30, 1958 YVQT: Johann Qms. BIV -Shdem Sept. 30, 1958 J. BACH PRosTHEsIs JoINTs 3 vSheets-Sheet 2 Filed March 14, 1956 T. n ksmr @MQ BM v un HBM DWJ Sept. 30, 1958 J, BACH 2,853,712

PRosTHEsIs JOINTs I Filed March 14, 1956 Y 3 Sheets-Sheet 5 28 Fla. 3

United Statesk Patent O PROSTHESIS JOINTS Johann Bach, Essen-Borbeck, Germany Application March 14, 1956, Serial No. 571,527

Claims priority, application Germany March 14, 1955 Claims. (Cl. 3--27) The present invention relates to prostheses. More particularly, the present invention relates to joints of prostheses such as the knee joint or ankle joint of an artificial leg. v

Known joints of the above type have several drawbacks. Thus, they are composed of extremely complicated mechanisms which are undesirably noisy during operation and which require constant maintenance and lubrication. Furthermore, they do not provide the wearer with a feeling of how the prosthesis is operating. Also, complicated devices are required with known joints for straightening the artificial limb after it has been flexed at the joint.

One of the objects of the present invention is to overcome the above drawbacks by providing a prosthesis joint of an exceedingly simple construction which includes a shaft capable of being shifted, e. g. transversely to its axis, Without any particular mechanism provided for producing such shiftability of the shaft.

Another object of the present invention is to provide a prosthesis joint capable of being noiselessly flexed.

A further object of the present invention is to provide a prosthesis joint which can be easily adapted to have operating characteristics peculiarly suited for a particular wearer of the prosthesis.

An additional object of the present invention is to provide a prosthesis joint which requires no maintenance, v

which requires no particular structure for straightening the joint after it is flexed, and which is capable of transmitting to the wearer a sense of the operation being carried out by the prosthesis.

Still another object of the present invention is to provide a prosthesis joint whose parts wear to an extremely small extent over a long period of time and whose parts are capable of absorbing shocks and capable of gradually responding in a yieldable manner to impulses transmitted to the joint by the wearer.

A still further object of the present invention is to provide a prosthesis joint capable of being incorporated into existing artificial limb parts, capable of cooperating with any desired accessories, and capable of being adapted to perform any special movements which may be required by the wearer.

With the above objects in view, the present invention mainly consists of a prosthesis joint which includes a pair of artificial limb parts and a shaft means carried by one of these parts and composed at least in part of a resilient yieldablev structure adapted to yield in response to forces applied by the wearer of the prosthesis. A bearing means is carried by the other artificial limb part and cooperates with the shaft means for providing relative turnable movement between the shaft means and the bearing means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be Pest understood from the following description of specific 2 embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 shows in a longitudinal sectional elevational view a prosthesis joint according to the present invention used as a knee joint of an artificial leg; l

Fig. 2 is a transversesectional view of the structurel of Fig. 1 taken along line 2-2 of Fig. 1 in the direction of the arrows;

Fig. 3 is a longitudinal sectional elevational view of a joint according to the present invention used as an ankle joint of an artificial leg; and

Fig. 4 is a transverse sectional view on an enlarged scale of the structure of Fig. 3 taken along line 4-4 of Fig. 3.

The prosthesis joint of the present invention is generally applicable to joints between the parts of any artificial limb, Aand in the drawings one example of a prosthesis joint according to the invention is shown in Figs. 1 and 2 applied to the knee of an artificial leg and another example of a prosthesis joint according to the invention is shown in Figs. 3 and 4'applied to the ankle of an artificial leg.

Referring to Figs. 1 and 2, it will be seen that the prosthesis illustrated includes a lower artificial leg portion 1 connected to an artificial knee joint 2 according to the present invention. The knee joint 2 includes a shaft means 3 having a resilient yieldable structure adapted to yield in response to forces applied by the wearer of the prosthesis. This resilient yieldable structure takes the form of cylindrical elastomer blocks 4 and 4a which form end portions of the shaft means and which are respectively connected to the ends of an intermediate rigid shaft portion 5. The elastomer blocks 4 and 4a may be made of rubber or a suitable plastic. These blocks 4 and 4a are fixed at their outer end faces respectively to a pair of metal plates 6 as by being vulcanized thereto,` and these plates 6 are respectively'formed with threaded openings which threadedly receive the screw members 7, respectively, which respectively pass through openings formed in a pair of carrier members 8 which are respectively fixed to opposite outer face portions of the articial limb part 1, as indicated in dotted lines in Fig. l. Thus, the shaft means 4, 4a, 5 is carried by the artificial limb part 1. At their inner end faces the elastomer shaft portions 4 and 4a are respectively fixed to a pair of plates 9, as

by being vulcanized thereto, and these plates fixedly carry a pair of threaded studs 10 which are in threaded engagement with threaded portions of an axial bore formed in the intermediate rigid shaft portion 5.

The cylindrical elastomer blocks 4 and 4a are respectively surrounded by a pair of bearing rings 11 which slidably engage the exterior surfaces of the blocks 4 and 4a, respectively, when the latter are unstressed, and these rings 11 form inner tubular bearings which are located turnably and slidably within an outer tubular bearing formed by the elongated bearing sleeve 12 which is in turn carried by the other artificial limb part 13 in a suitable opening formed in the latter. Bearing sleeve 12 may be fixed in any suitable way to the artificial limb part 13. Thus, elements 11 and 12 form a bearing means carried by artificial limb part 13 and cooperating with shaft means 4, 4a, 5, which is carried by artificial limb part 1, for providing relative turnable movement between the bearing means and the shaft means.

When a load is applied by the wearer to the above described prosthesis joint 2, the resilient yieldable structures 4 and 4a become deformed and the limb part 13 together with the bearing means 11, 12 and shaft means 4, 4a, 5 move downwardly to the dotted line position indicated in Fig. 2. A brake means is provided for braking the turning movement of the limb parts 1 and 13 with respect to each other, and this brake means includes 3, the bottom spherical face portion ofrthenlower portion` 14 `of"a'rtiiicial0 limb ypart 13 Hand ythe brake linings 18 carried by the dished spherical upper surface portion 16,0f the upper. part, ,17.of. thetlower artiiicial lirrib part, 1.` The -cooperatitm"ofelernentsj18 ,with facelbrakes or` blocks movement of. the joint', upon shifting downwar'dly ofjthe shait", means 3 iiijthemanner -described above.V i

Fig. l also illustrates that 'in 'order to limitfthefexing of the articial kneejoint ofthe invention thelimbl'part. 1 xedly carried a stop bar 19 lo'cated'inV the path ofV movement of a-resilientryieldabl e -stop block 20`.iixedly carried bythe upper articia'lflimb p`art`13 ,in .a recess ,ofV the latter into which the uppeY` portion ofibari19 freely extends. Y

The above describedA yie'ldabler deformation of .blocks 4 and v'4a during shifting of the shaft means and bearing The structure of`Figs. 3 and 4 includes an articial` ankle joint 21 interconnecting the .artificial foot. 22,with the lower artici'aljlegwpart l23'; As is particularly evident from Figj4, theH joint includes a resilient yieldable shaft means 24snrroundedby a tubular. bearing sleeveV or ring 25. The shaft means 24 is carried by thelower limb'part 22 through .the medium of a bifurcated carrier member 26. The shaft means 24 is turnable in a bearing means' described below and thus provides ilexing of the joint. Thebifurcated shaft means carrier 26 is provided with a pair of threaded extensions passing through bores of the artificial foot part 22 and carrying the nuts 27 which thus x the carrier 26 to the limb part 22. The bearing member v is fixed to an elongated extension 28 which passes through a bore of the upper'limb part 23 in the manner shown in Figs.` 3 and 4 and which threadedly carries'a nut for thus fixing the. bearing member 25 to the upper limb part 23. The'shaft means 24 is composed of a pair of 'elongated elastomer blocks 29 which are cylindrical, coaxial, and placedV in substantially end to end relation. These blocks extend into. aY tubular bearing sleeve 30 which is'surrounded at an :intermediate substantiallycentral portion by the bearing ring 25; Thefd sleeve 30 isfmade ofv a rigid material and aV set screw-`37 threadedly carried by the outer tubularbearing partj25 engages thenn'er tubular bearing part 30 toix theflatter toA part 25; WhenV a load is applied'tothis jointby the'f wearer, the elastomer blocks 29, which, extendV outwardlyV beyond the sleeve 30,Y are deformed and the upper limbV part 23 together with the bearing means A25, 30 andy shaft `meansr24'move downwardly, tliecarrier 26'providing -sufhcient clearance forthispurpose; Furthermore,v the joint structure of Figs. 3 and-4` permitsthe Yfoot part 22.` to yieldably and resiliently tilty laterally'with respect to the upper limb part 23.Y Y

In order'to provide a movement whichgis as natural as possible-,'the articiallimb structure of Figs. 3 and-14 includes an elastomer block 31 made of rubber or plastic in the same Vway'as theblocks 29, and this block 31 extends between and' engages the yheel portion 32 of the f oot partv22 and th'e'upper limb part 23, the end portions of theA elongated block 31 extending into suitable4 'recesses formed in parts 22 and 23, as is evident fromFig. 3. The block 31 is formed with an axial bore through which an elongated, ilexible, substantially unstretchable brake element 33 extends in engagement with the block 31. Brakeelement 33 may be a wire cable or a cable made of agsynthetvic material. The ends of the element .33 are fixed to, limb parts 22 nand 23 in themannershownin Fig. 3. Thus, element .33 extends through bores kof parts. y

22V .and 23 vwhich communicate With the recesses which receive element 31, and the lower end of element 33 is enlarged and engages the inner face of a recess formed in the bottom portion of heel part 32 while the upper end portion of element 33 extends through a spacer carried by limb part 23 and has an enlarged end engaging the top face of this spacer. i

As is evident from Fig. 4, the outer end faces of the blocks 29 are xed, as by vulcanizing, respectively to a pair of metal. discs 34 formed with threaded bores, respectively, which threadedly receive the fastening screws 35, respectively, which extend through openings formed in the free end portions of the upwardly'extending legs of carrier 26, respectively. A pair` of metal Vdiscs34z are respectively vulcanized to the inner faces of the blocks 29, and these discs 34a engage each other. If desired, the set screw 37 may extend through the sleeve 30 into engagement with the plates 34a to prevent relative movement betweenrthe latter` andthe sleeve.30',;in which case relative turning.,movement-between `shaft means 24 and bearing means 25, 30jtakes placerin the form of twisting of the blocks 29 with respect to-the sleeve 30.

In order to adapt the above described joints of the.;in-

vention to the characteristics of a particulary user, it is, possible with the embodiment` ofFi'gs. l andf2 to shift the rings 11 outwardly so that a lfesser portion ofthe blocks 4 and 4a extends beyond the rings-11l This would be done for arelatively heavy person. ,However,

it is also possible toV produce substantially .the sameresuits by choosing sleeves 11 of a particular length when assembling. the structure for use by a given person. Thus, sleevesy 11 are relatively` short in a prosthesis foruse byA arelatively light. person, because withV such short sleeves a considerable portion of theblocks 4 andfia can'extend beyond the sleeves to provide` easier deforma-..

tion of the blocks. On the other hand, longen-sleeves 11 4are chosen for a heavier person. y The sameresults can be producedwith'the embodiment oflFigs. 3'Jand`4 by choosing a sleeve 30 offa particular length suited for a. particular person so that the end portions ofthe blocks 29 extend to a greater or lesser extentb'eyond,thefsleeve 30 to provide the'desired-yieldability, A'lsQ,it/is vpos-Y sible ,to produce similar results by makingtheiblocks 4, 4a or 29 of a material which has a desiredamountof yieldability. given` any desired degree of'stiiness. i

In order to eliminate all 'maintenance with the strucy tureof the` invention, the elements of the bearing means are made. of. self-lubricating' materials.V 4Thel bearing sleeves Vorv ringsY can be' made of self-lubricating metalsL of the invention, the joint is capable of absorbing shocksV and is capable-'of gradually and'yieldably receiving the forces applied by the wearer. Furthermore the joints of the invention operate noiselessly and require no maintenance, this latter result being produced in part by the' self-lubricating'v properties ofl the Vbearing means.V Also, the wear of the-*parts is extremely small as compared toknown'constructions, and even when wear does occur there will be no noises which are produced in known constructionsrby they loose connection'between a Worn shaft andV bearing. Y

As was pointed outabove, thestructure ,ofthe inven-f tion presents ythe advantage of requiring ,no special'means. for urging the limb, parts backnto their, straightened, un.-v flexed condition. The.` above described possibilitiesfof- It' isV wellrknown that elastomers canberegulating the yieldable fo-rces to a particular wearer also regulates the force urging the limb parts to return to their untiexed condition in a manner adapting this latter force also to the particular characteristics of a given person.

The braking action provided with the construction of Figs. 1 and 2 takes place gradually and in a manner which is completely comfortable to the user.

It should be noted that it is possible to incorporate the joint structure of the invention into conventional arti-1icial limb parts and it is furthermore possible to combine with the structure of the invention any special control structure required in special cases.

It will be understood that each of the elements described above, or two or more together, may also iind a useful application in other types of prostheses differing from the types described above.

While the invention has been illustrated and described as embodied in a prosthesis joint, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.y

vVithout further analysis, the foregoing will so fuliy reveal the gist of the present invention that others can by applying current knowledge readily adapt it for variout applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning'and range of equivalents of the following claims.

What is claimed as new and desired to be secured by Letters Patent is: v

1. A prosthesis comprising, in combination, a pair of artificial limb parts; shaft means carried by one of said limb parts and having an elastomer portion adapted to yield in response to forces applied by the wearer of the prosthesis; a bearing ring surrounding and engaging said elastomer portion of said shaft means; and a bearing sleeve surrounding and carrying said bearing ring and carried by the other of said artificial limb parts.

2. A prosthesis comprising, in combination, a pair of artificial limb parts; shaft means carried by one of said limb parts and having an elastomer portion adapted to yield in response to forces applied by the wearer of theprosthesis; an inner tubular bearing part surrounding and engaging said elastomer portion of said shaft means; and an outer tubular bearing part surrounding and engaging said inner bearing part and carried by the other of said artificial limb parts.

3. A prosthesis comprising, in combination, a pair of artificial limb parts; shaft means carried by one of said limb parts and having an elastomer portion adapted to yield in response to forces applied by the wearer of the prosthesis; an inner tubular bearing part surrounding and engaging said elastomer portion of said shaft means; and an outer tubular bearing part surrounding and engaging said inner bearing part and carried by the other of said artificial limb parts, said inner and outer bearing parts being composed of a rigid, self-lubricating material.

4. A prosthesis comprising, in combination, a pair of artificial limb parts; shaft means carried by one of said limb parts and having an elastomer portion adapted to yield in response to forces applied by the wearer of the prosthesis; an inner tubular bearing part surrounding and engaging said elastomer portion of said shaft means; and an outer tubular bearing part surrounding and engaging said inner bearing part and carried by the other of said artificial limb parts, said inner and outer bearing parts being composed of a rigid, self-lubricating plastic.

5. A prosthesis joint as recited in claim l, a substantially unstretchable brake element extending between and connected to said artificial limb parts, said brake element being elongated and flexible; and an elastomer block extending between and engaging said artificial limb parts and being connected to said brake element.

6. A prosthesis joint as recited in claim l, a substantially unstretchable brake element extending between and connected to said artificial limb parts, said brake element being elongated and flexible; and an elastomer block extending between and engaging said artificial limb parts and being formed with a bore through which said brake element extends in engagement with said block.

7. A prosthesis joint comprising, in combination, a pair of artificial limb parts; an intermediate rigid shaft portion; a pair of elastomer shaft portions fixed respectively to and extending beyond opposite ends of said intermediate shaft portion; a pair of bearing rings respectively surrounding said elastomer shaft portions, the

. latter' respectively having outer portions respectively extending beyond said bearing rings; means fixing said outer portions of said elastomer shaft portions to one of said artificial limb parts; and a bearing sleeve carried by the other of said artificial limb parts and surrounding and carrying said bearing rings.

8. A prosthesis joint comprising, in combination, a pair of artificial limb parts; a pair of elongated coaxial elastomer shaft portions located substantially in end to end relation and being carried by one of said artificial limb parts; a bearing sleeve into which said Shaft portions extend, said shaft portions each having an outer end portion located beyond said bearing sleeve; and a bearing ring surrounding and engaging said bearing sleeve at an intermediate portion thereof and carried by the other of said artificial limb parts.

9. A prosthesis joint as recited in claim 1, and brake means cooperating with said artificial limb parts for braking the turning movement thereof relative to each other.

10. A prosthesis joint as recited in claim 1, a pair of carrier members connected to said one limb part and respectively ixed to opposite ends of said shaft means for supporting the latter on said one limb part.

References Cited in the tile of this patent UNITED STATES, PATENTS 1,383,364 Worman July 5, 1921 1,911,440 Desoutter May 30, 1933 2,066,599 Willett Jan. 5, 1937 2,390,920 Caron Dec. 11, 1945 2,551,537 Havens May 1, 1951 2,629,105 Woodall Feb. 24, 1953 2,696,011 Galdik ----2 Dec. 7, 1954 2,752,607 Bidwell July 3, 1956 

